TABLE SHOWING EVAPORATION, FROM WATER-SURFACE EXPOSED IN SHALLOW TANKS, NEAR WATER OR GROUND SURFACE. ===================================+========+==================== | Years. | Inches. -----------------------------------+--------+-------------------- Rothamsted, England | 9 | 17.80 (16.6 to 18.4) London, “ | 14 | 20.66 Oxford, “ | 5 | 31.04 Munich, Germany | ? | 24.00 Emdrup, Denmark | 10 | 27.09 Cambridge, Massachusetts | 1 | 56.00 Syracuse, New York | 1 | 50.20 Logan, Utah | 1 | 52.39 Tucson, Arizona | 1 | 75.80 Fort Collins, Colorado | 11 | 41.00 Fort Bliss, Texas | 1 | 82.70 San Francisco, California | | 45 to 50 Sweetwater Reservoir, | | San Diego, California | 1 | 57.6 Peking, China | ? | 38.80 Demerara, South America | 3 | 35.12 Bombay, East India | 5 | 82.28 Petro-Alexandrowsk, West Turkestan | ? | 96.40 Kimberley, South Africa | ? | 98.80 Alice Springs, South Australia | ? |103.50 -----------------------------------+--------+-------------------- This table, the data for which are taken from various sources, exhibits clearly the enormous variations in evaporation in different countries, and even in localities not very remote from each other. The low evaporation near London is doubtless due to its foggy and hazy atmosphere, but it is not clear why Rothamsted should show so low an evaporation compared with Oxford. Tropical Demerara stands nearest to Oxford in its evaporation; Bombay indicates its location on the hot and arid west coast of India, despite its nearness to the sea. The inland localities in the desert regions of South Africa, Australia and Western Turkestan, show how enormous may be the losses from evaporation of irrigation water, unless the latter is applied with special care for their prevention. Thus, with the wasteful methods of irrigation prevailing in portions of the American arid region, it is certain that in many cases 50% and more of the water evaporates before it reaches the crops.